Battery device and electric bicycle

A battery device comprising:

• a battery;
• a battery mount including a first support and a second support respectively supporting a first end and a second end of the battery to allow attachment/detachment of the battery;
• a first movement restrictor provided at the first end of the battery;
• an engaging portion provided in the first support and movable between an engaged position to engage with the first movement restrictor and a disengaged position in which engaging portion is not engaged with the first movement restrictor;
• and
• a second movement restrictor provided in the first support to position the engaging portion at the engaged position to restrict the engaging portion from moving toward the disengaged position;
• wherein
• the battery is removable from the battery mount in a removal direction that is either a direction in which the battery is pivoted around the second end of the battery, or a direction perpendicular or substantially perpendicular to a longitudinal direction of the battery;
• the engaged position and the disengaged position of the engaging portion extend along a widthwise direction or the longitudinal direction of the battery;
• and
• the engaged position is a position where the engaging portion is in engagement with the first movement restrictor to make the battery non-removable from the battery mount, and the disengaged position is a position where the engaging portion is not in engagement with the first movement restrictor to make the battery removable from the battery mount.